PROJECT SUMMARY/ABSTRACT Associations between characteristics of the neighborhoods in which older people live and late-life disparities in chronic illness have been the subject of a rapidly growing field of research. For low-income and minority elders with chronic illness, disparities in access to and quality of care contribute to disparities in the burden of illness. Research on chronic illness has also underscored the links between inadequate physician oversight, potentially preventable hospitalizations, and poor health outcomes. However, little is known about the ways in which neighborhood environmental factors - beyond local supply of medical services - inform how urban older adults with chronic illness use physician services to manage their health. This study addresses this gap by examining the relationships between neighborhood built environment (e.g. walk-ability, access to public transit), use of physician services, and preventable hospitalizations and emergency department visits among elderly, chronically ill Medicare beneficiaries who live in New York City. Specifically, the study aims to: 1) Examine associations between neighborhood built environment and physician service use among urban, chronically ill older adults; 2) Determine whether and to what extent variations in the built environment influence potentially preventable hospitalizations and emergency department visits; and 3) Reassess findings from Aims 1 and 2 by applying: (i) alternative modeling techniques; and (ii) tests of endogeneity to address the potential sorting of patients into neighborhoods with different characteristics based on service use and outcomes. The study will be based on longitudinal analysis of existing data on a sample of NYC-dwelling Medicare beneficiaries age 65 and older, linking individual characteristics and service use measures with small area- level data from other sources. Analyses will focus on patients with congestive heart failure and diabetes - two major contributors to preventable hospitalizations. This study will provide insight into the interdependence of clinical, social, economic, and environmental factors that influence quality of chronic illness care and, ultimately, quality of life, for older adults with multiple co-morbidities. The proposed research will apply and expand on the candidate's training throughout the K01 award period, including advanced methodological training in epidemiology and health economics. The training and research activities will lay the foundation for an R01 application in the later years of the award. Findings from this study and future research will ultimately be applied toward developing effective interventions to improve access to, continuity, and quality of ambulatory care for chronically ill elders living in underserved communities and, in turn, mitigate late-life health disparities.